The present invention essentially comprises an improvement over the applicant's prior U.S. patent, No. 4,067,334, issued Jan. 10, 1978, and in which T-shaped frame, of which the stem comprised a handle, supported a slide along the top of the frame in which a hypodermic syringe was detachably mounted for quick initial injection of the needle of the syringe into the flesh by means of a spring which effected only such limited initial movement very rapidly. An additional slide movable along the top of the frame was actuated by a fluid-operated piston in a cylinder, one end of the cylinder being connected to a squeezable bulb which injected fluid in said end of the cylinder to move the plunger forwardly for engagement with the handle of the syringe to effect discharge of the contents of the syringe after the needle had been inserted into the flesh.
It has been found that this prior device, while mechanically satisfactory, rendered movement of the plunger of the fluid-operated unit relatively slow, in addition to requiring said fluid-operated cylinder unit which consumed a certain amount of space and also rendered the entire unit somewhat more complex than was desirable. Accordingly, additional research and contemplation has resulted in the present invention in which said fluid-operated cylinder unit and the compressible bulb has been eliminated and several embodiments of rapidly-operated motion-multiplying means have been substituted for the aforementioned cylinder unit and compressible bulb which also has resulted in rendering the structure capable of being made in a somewhat smaller size than that of the prior patent and, in addition, the actuation by the motion-multiplying means referred to renders the movement of the hypodermic cylinder more direct and positive than that afforded by the squeezable bulb due to employing several embodiments of trigger-type means which actuate the motion-multiplying mechanisms.
The use of tripper-type mechanisms in self-injecting type syringe devices is not new and examples of such devices are found in the following prior U.S. patents: Nos.
2,816,546 Luhmann Dec. 17, 1957 PA1 2,892,457 Sturtz June 30, 1959 PA1 2,942,603 Geyer June 28, 1960 PA1 3,064,650 Lewis Nov. 20, 1962 PA1 1,242,060 (British)--Published Aug. 6, 1968
None of the structures illustrated in the above-cited patents include motion-multiplying mechanism which operates between the trigger of the device and the carriage which moves the plunger-actuating member forward to discharge the contents of the hypodermic syringe. In fact, the patent to Geyer has a gear-type motion-changing device which actually produces a slower motion of the plunger than that of the trigger, whereby the operation is the reverse of that of the present invention.